private JPanel getMixerOptionsPanel() {
    if (mixerOptionsPanel == null) {
      mixerOptionsPanel = new JPanel();
      mixerOptionsPanel.setBorder(
          BorderFactory.createTitledBorder(BorderFactory.createEtchedBorder(), "Mixer"));

      mixerOptionsPanel.setLayout(new GridBagLayout());
      GridBagConstraints c = new GridBagConstraints();

      c.anchor = GridBagConstraints.NORTHWEST;
      c.fill = GridBagConstraints.NONE;
      c.weightx = 1;

      c.insets = new Insets(8, 4, 0, 0);
      mixerOptionsPanel.add(new JLabel("Select mixer:"), c);

      c.gridy = 1;
      mixerOptionsPanel.add(getMixerComboBox(), c);

      c.gridy = 2;
      mixerOptionsPanel.add(getMixerDefaultButton(), c);

      c.insets = new Insets(16, 4, 0, 0);
      c.gridy = 3;
      mixerOptionsPanel.add(new JLabel("Enable mixer features:"), c);

      c.insets = new Insets(6, 0, 0, 0);
      c.gridy = 4;
      mixerOptionsPanel.add(getEnableMixerVolumeCheckBox(), c);

      c.insets = new Insets(0, 0, 0, 0);
      c.gridy = 5;
      mixerOptionsPanel.add(getEnableMixerPanCheckBox(), c);

      if (AudioSystem.getMixerInfo().length == 0) {
        for (Component child : mixerOptionsPanel.getComponents()) {
          child.setEnabled(false);
        }
      }
    }
    return mixerOptionsPanel;
  }
  private JPanel getSoundOptionsPanel() {
    if (soundOptionsPanel == null) {
      soundOptionsPanel = new JPanel();
      soundOptionsPanel.setBorder(
          BorderFactory.createTitledBorder(BorderFactory.createEtchedBorder(), "Sound Effects"));

      soundOptionsPanel.setLayout(new GridBagLayout());
      GridBagConstraints c = new GridBagConstraints();

      c.fill = 1;
      c.weightx = 1;
      c.anchor = GridBagConstraints.NORTHWEST;

      c.gridwidth = GridBagConstraints.REMAINDER;
      soundOptionsPanel.add(getEnableSoundCheckBox(), c);
      soundOptionsPanel.add(getEnableGunshotCheckBox(), c);
      soundOptionsPanel.add(getEnableBulletHitCheckBox(), c);
      soundOptionsPanel.add(getEnableRobotDeathCheckBox(), c);
      soundOptionsPanel.add(getEnableWallCollisionCheckBox(), c);
      soundOptionsPanel.add(getEnableRobotCollisionCheckBox(), c);

      c.insets = new Insets(10, 0, 0, 10);
      c.gridwidth = 1;
      c.fill = 0;
      c.weighty = 1;
      c.weightx = 0;
      soundOptionsPanel.add(getEnableAllSoundsButton(), c);
      c.weightx = 1;
      c.gridwidth = GridBagConstraints.REMAINDER;
      soundOptionsPanel.add(getDisableAllSoundsButton(), c);

      if (AudioSystem.getMixerInfo().length == 0) {
        for (Component child : soundOptionsPanel.getComponents()) {
          child.setEnabled(false);
        }
      }
    }
    return soundOptionsPanel;
  }